This invention relates to pipe repair fittings designed for pipes through which liquid passes under pressure. More particularly, the repair fittings of this invention are adapted for simple installation in existing piping systems to effectively surround and seal ruptures or leaks which have developed in the piping system at coupling or pipe joinder positions.
The repair or ruptures or leaks in existing piping systems has presented a long standing and continuing problem in the art. Numerous types of fittings have been proposed with the intent of providing a device to be installed around a rupture or leak to repair the leak without requiring disassembly of the existing system and subsequent reassembly of the system with replacement parts installed. It will be recognized that such disassembly and reassembly activities are time consuming and costly in terms of labor and parts. Also such repair activities are inconvenient since the system must be shut down while the repair is in process. However, the fittings previously proposed have not been completely satisfactory from the standpoint of providing effective and reliable closing and sealing of the rupture or leak at the pipe coupling or joinder positions with devices which can be produced at commercially acceptable cost.
Repair fittings which have been proposed and which can be economically produced are those which employ strips of gasket material to seal the pipes on opposite sides of the rupture or leak. Exemplary of such fittings are the pipe joint protectors disclosed in U.S. Pat. No. 320,771. These fittings, however, have presented problems in effectiveness of sealing leaks because of the criticality of proper alignment of the single gasket arrangements which have been proposed. If the unitary end gasket fails for some reason such as improper alignment of the gaskets or the use worn gaskets, there is no secondary seal to prevent leakage. In an attempt to overcome this problem other fittings have been proposed which utilize complete elastomeric sleeves bonded to metal shell bodies and the bodies are compressively connected so that the seal members are joined to form a fluid tight seal. Such arrangements are effective for sealing leaks but are unadvantageously costly to produce. An example of this latter form of repair fitting is disclosed in United States Letters Patent 3,517,701.